Matt Cain has been scratched from today's scheduled start against Colorado with inflammation in his throwing elbow. Manager Bruce Bochy said the injury is not serious, but the staff surely will be cautious with such a precious arm.

"Obviously we hope it doesn't have to take missing more than one start," Bochy said. "We'll see where he's at in a couple of days. Now's the time to back him off and calm this down a little bit."

Bochy said Cain felt soreness after his first Cactus League start Sunday and had an MRI exam, which revealed the inflammation. He pitched two shutout innings in that game.

Bochy assures Zito: Bochy conveyed the same message during a private meeting with Barry Zito and in a session with reporters: "He'll be our fourth starter," Bochy said.

The Chronicle reported earlier in the day that Zito was walking a fine line with the organization. The paper quoted a source saying the left-hander's status in the rotation was "definitely not safe" and the team might consider releasing Zito and eating the remainder of his $126 million contract.

"Barry and I talked," Bochy said. "Believe me, there have been no conversations anywhere near what the article was about, not with Brian (Sabean), myself, the staff, everyone. I told Barry that."

There are other starters in camp, including 2006 National League Championship Series MVP Jeff Suppan and prospect Clayton Tanner. Asked if they have any chance to supplant Zito for a spot in the rotation, Bochy said, "You do stay open-minded with the competition going on, whether it's in the outfield, infield or the pitching staff. Right now, we've come up with a game plan and that's Barry Zito going in the fourth game."

Bochy also said he has no problem with Zito's conditioning, another point raised in The Chronicle, though Bochy revealed that Zito changed his offseason workout routine at the team's behest.